Shape Memory Alloy Actuator for Turbojet Bypass Shutter
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Solution Overview
Problem
Conventional actuating devices for bypass air bleed systems in turbojet engines, such as those using hydraulic or mechanical jacks, are heavy, bulky, and require high-pressure fluids or electric power, which are inefficient and cumbersome.
Innovation Solution
A two-way shape memory alloy actuator system that switches between two stable states based on temperature, utilizing thermal energy from the engine to actuate bypass air bleed shutters, eliminating the need for high-pressure fluids and electric power, and is designed to be lightweight and compact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic or mechanical jacks are used to actuate bypass air bleed shutters, then the shutters can be effectively actuated, but the actuating device becomes heavy and bulky
Solution Approach 1:
The patent replaces traditional mechanical actuating systems (hydraulic jacks, mechanical jacks with motors) with a shape memory alloy-based actuating system. The shape memory alloy elements directly convert thermal energy from engine gases into mechanical displacement to actuate the shutters, eliminating the need for heavy mechanical components, hydraulic fluids, and electric drive systems.
Solution Approach 2:
The shape memory alloy actuating system utilizes thermal energy from the engine's own operating gases (exhaust or compressor air) to power the shutter actuation. This self-service approach eliminates the need for external power sources, hydraulic pumps, or electric motors, thereby reducing the weight and complexity of the actuating device while maintaining reliable shutter control.
2Ease of operation
If hydraulic jacks are used for actuation, then shutter control is achieved, but high-pressure fluids and complex conveying means are required
Solution Approach 1:
The patent substitutes complex hydraulic or mechanical actuating systems with a shape memory alloy-based system. The shape memory alloy elements directly convert thermal energy from engine gases into mechanical displacement to actuate the shutters, eliminating the need for hydraulic fluids, high-pressure conveying systems, electric motors, and associated control wiring.
Solution Approach 2:
The patent utilizes pneumatic principles by directing hot gases or compressed air from the engine through channels that heat the shape memory alloy elements. This thermal-pneumatic approach replaces complex hydraulic fluid conveying systems with simpler gas flow paths that are already present in the engine structure, reducing device complexity while maintaining effective shutter control.
3Ease of operation
If mechanical jacks with electric motors are used, then shutter actuation is achieved, but electric drive motors and wiring are required
Solution Approach 1:
The patent replaces electrically-driven mechanical actuating systems with a shape memory alloy-based system. The shape memory alloy elements directly convert thermal energy from engine gases into mechanical displacement to actuate the shutters, eliminating the need for electric drive motors, current generators, and extensive wiring harnesses.
Solution Approach 2:
The shape memory alloy actuating system utilizes thermal energy from the engine's own operating gases to power the shutter actuation. This self-service approach eliminates the need for external electric power sources and complex electrical control systems, thereby reducing the weight and complexity of the actuating device while maintaining reliable shutter control.
4Ease of operation
If conventional actuating systems are used, then shutter control is achieved, but the system is cumbersome and inefficient
Solution Approach 1:
The shape memory alloy actuating system utilizes waste thermal energy from the engine's operating gases (exhaust or compressor air) to power the shutter actuation. This self-service approach converts otherwise wasted thermal energy into useful mechanical work, eliminating the need for external power sources and improving overall system efficiency.
Solution Approach 2:
The patent replaces inefficient mechanical and electrical actuating systems with a shape memory alloy-based system that directly converts thermal energy into mechanical displacement. This substitution eliminates energy losses associated with hydraulic fluid compression, electric motor inefficiencies, and mechanical transmission losses, thereby improving actuating system efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a lightweight, compact, and efficient actuation system that effectively manages air bleeding without the drawbacks of traditional systems, enhancing the operational stability of turbojet engines by simplifying fluid circuits and reducing ancillary system complexity.
Implementation Method 1
the bypass air bleed shutters are actuated not by jacks but by shape memory alloy actuators which are activated by the thermal energy from high-temperature gases
Data Source
AI summary
An actuating device for opening and closing at least one shutter in a gas turbine engine, such as a turbojet engine, includes at least one actuator made of a two-way shape memory alloy having a first stable state at a first temperature in which state it actuates either the opening or the closing of the shutter, and a second stable state at a second temperature, in which state it actuates either the closing or the opening of the shutter, respectively.